Anxiety disorders are relatively frequent in the pediatric population and are responsible for significant morbidity. We are currently conducting a clinical trial of fluvoxamine treatment of childhood and adolescent-onset anxiety disorders, specifically separation anxiety disorder, generalized anxiety disorder, and social phobia. This study is an opportunity to utilize a molecular genetic research design to study the genetics of anxiety in a pediatric population. This proposed study will examine three primary associations: 1) the presence of childhood-onset anxiety disorders and serotonin (5HT) related candidate genes, 2) temperament and 5HT related genes, and 3) response of childhood anxiety to treatment with fluvoxamine and 5HT related genes. Identification of specific genetic factors may lead to advanced prevantative and treatment strategies.